1. Field of the Invention
This invention is generally related to cylinder lock and key sets of the type used in automotive primary and secondary lock systems and is specifically directed to a compact cylinder lock and key set including a reversible double-bitted key.
2. Description of the Prior Art
Cylinder lock and key sets for automotive use are well known. Typically, the cylinder is housed in a cylindrical opening provided in a housing. The housing is mounted in a cavity in the implement or apparatus to be controlled by the lock. For example, it is typical to provide a cylindrical lock and key set for the ignition of the automobile on the steering column, to provide an instrument panel lock such as a storage compartment or glove compartment, door locks and rear deck locks. The cylinder typically includes an axial key way adapted for receiving a bitted or notched key which engages tumblers housed in the cylinder. The tumblers are normally biased radially outwardly from the cylinder into engagement with the housing to prohibit rotation of the cylinder for locking the lock. When a properly bitted key is inserted in the key way of the cylinder and engages like encoded tumblers, the tumblers are withdrawn from the housing into the cylinder, permitting rotation of the cylinder to unlock the apparatus or to activate a system such as an ignition system.
Over the years, it has become more desirable to utilize single keys for access to both the primary (ignition) and secondary (instrument panel, door and deck) locks of a vehicle. It has also become desirable to utilize reversible keys so that the key may be readily inserted in the key way irrespective of its orientation.
The prior art reversible key systems required enlarged cavities for housing the cylinder lock sets. For example, reversible key-type secondary locks on many American cars require housing cavities with a minimum diameter of over 15 millimeters. This has created some problems when making secondary locks, particularly for instrument panel adaptation.
By way of example, the cavities provided in instrument panel systems for automobiles typically made by General Motors have maximum cylinder capacities of under 13 millimeters. In order to adopt reversible double-bitted keys for such locks, it is either required that the cylinder and key be reconfigured to fit into the available architecture (13 millimeters or less in diameter) or that the vehicle manufacturer adopt a larger cavity. In order for a vehicle manufacturer to adopt larger cavities, it is required that the entire instrument panel or other lock actuated mechanism be retooled, generating an expense in the tens of millions of dollars.
Therefore, it is desirable to provide a cylinder lock and key set having a reversible double-bitted key which is configured to fit into the standard architecture. None of the prior art double-bitted reversible lock and key sets meets this objective. This is primarily because the key width is dictated by torque requirements, and the key width caused an outward progression of the size of the key way, the cylinder, the tumbler window and ultimately the cavity for accepting the cylinder system. Therefore, there remains a need for a reconfigured double-bitted reversible lock and key set which is adapted for accommodating the standard architecture of many current vehicle systems.